Circuit interrupting apparatus



July 1l, 1944- H. A. TRlPLET-r '2,353,528

CIRCUIT INTERRUPTING APPARATUS July ll, 1944.

H. A, TRIPLETT `2,353,528 CIRCUIT INTERRUPTING APPARATUS Filed May 28,1942 5 Sheets-Sheet 2 July 11', 1944. H, A, TRiPLET-r n 2,353,528

CIRCUIT INTERRUPTING APPARATUS Filed May 28, 1942 5 Sheets-Sheet 5 U BYf WW im July 1l, 1944. H. A. TRIPLETT CIRCUIT INTERRUPTING APPARATUSFiled May 22a,` 1942 5 Sheets-Sheet 5 mw v INVENTOR. v?. Tz/OSZLT BY im@MMM Patented July 11, 1944 2.353.528 cnwm'r m'raaammo APPARATUS Hugh A.Triplett, Wllmctte. lll., assigner to Schweitzer-Conrad, Inc., Chicago,Ill., a corporation of Delaware Application May 28, 1942, Serial No.444,854

(Cl. 20o- 120) 24 Claims.

lb invention relates, generally. to circuit interrupting apparatus andit has particular relation to high voltage circuit interrupters in whichthe circuit opening is initiated by the blowing of one or more fusibleelements.

An object of my invention is to provide for releasing an arcextinguishing nuid and for directing it into the arc space along asubstantially straight and undeviating path.

Another object of my invention is to provide lor lost motion between areservoir containing a material which when released is an arcextinguishing medium and a tubular terminal through which the arcextinguishing fluid is released into the arc space in order to etl'ectthe release of the arc extinguishing fluid when the tubular terminalmember has moved to a predetermined position.

A further object of my invention is to provide for hermetically sealingthe reservoir to the tubu lar terminal member while still permittingrelative movement therebetween to eil'ect release of the arcextinguishing uid.

It is also an object of my invention to provide an improved form of lowtemperature fusible element construction for a high amperage fuse.

Still another object of my invention is to pro- Vide a low resistanceconducting path to the movable tubular terminal member of a circuitinterrupter both before the terminal member moves to extend andextinguish the arc and while it is moving to the open circuit position.

A further object of my invention is to provide for cooling andcondensing the products of the arc formed o'n operation of a circuitinterrupter by passing the same through a restricted passageway one ofthe walls of which at least is formed of material which is capable ofevolving an arc cooling medium due to the heat of the arc products.

A still further object of my invention is to provide for arresting themovement of the reservoir containing the arc extinguishing fluid and topermit the tubular terminal member to continue to move to effect releaseof the arc extinguishing fluid.

Other objects of my invention will, in part, be

obvious and in part appear hereinafter.

For a more complete understanding of the nature and scope of myinvention reference can be had to the following detailed descriptiontaken in connection with the accompanying drawings in which:

Figure l is a view, partly in section and partlyk in front elevation,showing one embodiment of my invention;

Figures 2 and 3 are top and side views of a piercing pin and supportsolder therefor arranged to be mounted at the end of the tubularterminal of the circuit interrupter shown in Figure l for piercing thediaphragm of the reservoir or capsule containingy the material whichwhen released is an arc extinguishing fluid;

Figure 4 is a view, in side elevation, of the circuit interrupter shownin Figure 1:

Figures 5 and 6 are views, in side elevation, of the upper line terminalshowing the movable stop in different positions;

Figure 7 is a top plan view of the and its support as shown in Figure 5;e

Figures 8A and 8B, taken together, are a lef-..-n gitudinal sectionalview of another embodimen.,h 0i' my invention; and

`Figures 9A and 9B, taken together, are a. 1ongitudinal sectional viewof still another embodiment of my invention.

Referring now particularly to Figures 1 and 4 of the drawings, it willbe observed that the circuit interrupter construction there shown issimilar to one of the embodiments of circuit interrupter constructiondisclosed in my copending application, Serial No. 224,696, flled August13, 1938. The circuit interrupter here shown comprises upper and lowerterminals Il and I2 that are mounted on suitable insulators Il and Ilwhich are carried by a suitable base member IB, such as a channel ironbase. On the lower terminal I 2 there is mounted a replaceable fusecartridge shown generally at I6.

The replaceable fuse cartridge 'I0 comprises a housing I1 of suitableinsulating material, such as a fiber lined "Bakelite tube, having atermimovable stop nal Il at its lower end which is adapted to be securedto the lower terminal I2 by clamp means, shown generally at 20. At itsupper end the insulating housing I1 is provided with a metallic ferrule2| having an eye portion 22 integrally formed therewith for receiving ahook stick for placing the cartridge in operative position and forremoving it therefrom.

Within the insulating housing i1 there is a liner of solid arcextinguishing material, such as magnesium borate or boric acid, in theform of rings 26 which are stacked one above the other so as to providea bore 21' therethrough. A tubular terminal member 2B is mounted formovement through the bore 21 and it is provided with a centrallongitudinally extending opening or passageway 29 for a purpose whichwill presently be apparent. yIt will be observed that the tubularterminal member 28 is prevented from upward movement relative to theterminal member i8 by a strain wire 30. A fusible element Il, preferablyin the form of a silver wire, interconnects the terminal member Il andthe tubular terminal member 28 to provide a calibrated fusible section.

Near its upper end the tubular terminal member' 28 .is threaded into atwo-armed contact member 32 which is arranged to cooperate withspring-biased contact lingers l! that are carried by the upper terminalIl. During the normal operation of the circuit interrupter the principalportion of the current flowing between the terminals il and l2 flowsthrough the contact fingers il and contact member 32 into the tubularterminal member Il.

It will be observed that a sleeve I1 is threaded onto the upper side ofthe contact member 32 and that this sleeve is provided with integrallyformed oppositely extending arms il which interfit with suitably shapedslots in a yoke Il. The yoke il is provided with oppositely extendingshafts 4l which are mounted in suitable bearings Il carried by the upperterminal Il. Coilsprings 42, act between the shafts 4l and the bearingsIl. By means of the coil springs Il it will be observed that the tubularterminal member 1l is normally biased upwardly but that auch movement isrestrained by the strain wire ll. On flow of predetermined current inthe circuit in which the circuit interrupter is connected the fusibleelement Il will be fused. This will be followed by fusion of the strainelement 3l..

'Ihereupon the tubular terminal member 2l will be restrained no longerbut will be withdrawn through the bore 21 by the springs Il. The arcincident to the circuit interruption will be drawn between the lower endof the tubular terminal member Il and the terminal member 'Il at thelower end of the insulating housing l1.

The present invention is particularly directed to the provision of meansfor assisting in extinguishing relatively low current arcs between theterminal members Il and 2i and also for scavenging the walls of the bore21 after the arc has been interrupted so as to remove therefromconducting particles and foreign material which might form a conductingpath tending to facilitate subsequent breakdown or iiashover. In orderto effect this desired operation a reservoir or capsule I3 is mounted inthe sleeve I1. The reservoir or capsule I3 contains a material, such ascarbon dioxide, which, when released. forms an arc extinguishing fluid.A rupturable diaphragm M seals the reservoir or capsule I3. It will beunderstood that any suitable reservoir or capsule I! can be employedsuch as the Sparklet type of capsule that is now on the market. It willbe understood, however, that other type! of reservoirs or capsules canbe employed. The reservoir or capsule Il is held in place by a coilcompression spring 4l. In order to seal the reservoir or capsule Il tothe tubular terminal member Il and at the same time permit relativemovement therebetween a flexible bellows 4t is provided, as shown, 'forenclosing the upper end of the reservoir or capsule Il. The flexiblebellows Il is secured, as by soldering, to the upper end of the sleeveI1.

In order to puncture the diaphragm M a pin or needle 41 is carried on abridge ll, Figures 2 and 3, which is located at the upper end of thetubular terminal member 1I. The pin or needle 41 may be any suitablesharp instrument such as a phonograph needle which will penetrate thediaphragm 4| and rupture the same.

It will be understood that, because of the coil compression spring il,the reservoir or capsule Il moves upwardly with the tubular terminalmember 2l under the influence of the coil springs 42 after the strainelement Il has blown. After the tubular terminal member 2l has beenmoved upwardly through the bore 21 for a considerable distance, it isdesirable to rupture the diaphragm 4I and release the arc extinguishingfluid. In order to accomplish this a stop Il ia mounted on abracket Il,Figure 5, extending from the upper terminal Il and is arranged, asshown. in the path of upward movement of the upper end of the flexiblebellows 4l. When the tubular terminal member 2l is moved upwardlysufilciently far to have the upper end of the flexible bellows l. engagethe stop 4I, further upward movement of the reservoir or capsule Il isprevented. However. because of the coil comp'ression spring Il and theflexible bellows It. the tubular terminal member I8 continues to moveupwardly a slight distance during which time the pin or needle l1 iscaused to rupture the diaphragm Il. The arc extinguishing materialwithin the reservoir or capsule Il is then released and it flowsdirectly through the passageway il into the arc space between theterminals Il and 2l. Since the arc extinguishing fluid is anon-conductor, it materially asista in extinguishing the arc,particularly lcw current arcs. by nlling the arc space with anon-conducting medium. and, because of the blast action of the releasedarc extinguishing material, the conducting particles in the arc spaceare blown out of the lower end of the bore l1. In addition. after thearc has been extinguished the arc extinguishing nuid will continue toflow from the reservoir or capsule Il through the passageway il underconsiderable pressure. 'I'his will scavenge the walls of the bore 21 andblow out conducting particles or carbon deposits which might tend toform a conducting path that would facilitate arcover or breakdown at alater time.

As indicated hereinbefore the two armed contact member 32 and thecontact nngers J8 form the main conducting path between the tubularterminal member 2l and the upper terminal Il. Shortly after the tubularterminal member 2l begins to move upwardly, the contact member Ildisengages the spring contact fingers Il. All of the current is thentransferred to the arma il and the yoke Il. With a view to providing alow resistance path between the yoke II and the upper terminal Il, aflexible conductor Il interconnects the yoke it and one of the bearingsll. It will be understood that the flexible conductor Il carriessubstantial current only during the circuit interrupting operation afterthe contact member l2 has disengaged the contact fingers Ii.

After the circuit interruption has been completed, the tubular terminalmember il is held in the upper position against the stop Il by the coilsprings 42.

In order to facilitate replacing the blown cartridge il it is desirableto provide means for removing the arms Il from the yoke Il. For thispurpose the stop l0 is pivoted at I2. Figure s, on me bracket n ma has sring sa integrally formed therewith into which the prong of a switchstick can be inserted for moving the stop Il from the position shown inFigure 5 to that shown ln Figure 6 of the drawings. Normally the stop Iltends to swing downwardly under the influence of gravity and is held inthe position shown in Figure 5 of the drawings by an ear Il whichengages the central iiange portion il of the bracket BI.

When the stop Il is moved to the alternate position as shown in Figure 6of the drawings, the yoke I! is permitted to move upwardly until thestops Il integrally formed 'therewith engage the undersides of thebearings 4l.

assasas The prong of the hook stick then can be inserted in theeye 22and, after the clamp 2l has been released. the blown cartridge il can beremoved and replaced with an unblown cartridge.

It will be understood that the positions of the stops Il are suchrelative te the bearings Il that, before the stop 4l is moved from theposition shown in Figure 5 of the drawings, and the cartridge I. hasblown, they are spaced a slight distance from the underside of thebearings Il. This insures that the pin or needle 41 can be moved throughthe full stroke to rupture the diaphragm Il. The upward thrust of thesprings 42 is arrested solely by the stop 4s in the first instance.After the stop Il is moved to the alternate position shown in Figure 6of the drawings, the yoke Il then moves upwardly slightly under mise theundersides of the bearings 4I.

It will be understood that, as soon as the prong .of the switch stick isremoved from the eye ring Il, the step v4l will immediately swingdownwardly under the innuence of gravity. There is then no likelihoodthat the operator will forget te replace the stopv Il since it isautomatically restored to its operative position, While the stop Il willengage one side of the flexible bellows 4l in the released position,this does not interfere with the removal of the cartridge il.

The clamp 2l can be of any suitable type. The construction shown isdescribed in more detail in Patent No. 2,147,316, of Allan Ramsey. Itincludes a clamp arm Il having an integrally formed socket portion Ilfor receiving the prong of a switch stick. The clamp 2l while providinga low resistance conducting path between the terminal member Il and thelower terminal I2 still permits a slight oscillation of the cartridge'I6 as is required by the swinging yoke l! in moving from one position toanother during the circuit interrupting operation.v

With a view to facilitating the positioning of the cartridge II inoperative position the terminal member il is provided with oppositelyextending arms 02 which are arranged to interiit with suitable recessesin arms extending from the lower terminal i2. By this means the positionof the cartridge il can be accurately determined.

In Figures 8A and 8B of the drawings there is shown a circuitinterrupter construction in which several novel features areincorporated. The circuit interrupter is indicated, generally, by thereference character Il and is so designed andconstructed that it can beplaced in and removed from standard fuse clips mounted on suitable lineterminals. The circuit interrupter 10 is intended to be removed as aunit and replaced by a new or rebuilt cartridge of the same type andcharacter.

It will be observed that the circuit interrupter 1I comprises terminalsIi and l2 which may be formed of copper tubing and which are adapted tobe located in the respective fuse clips. Metalliv,` iittings Il and 14are threaded into the ends of the tubular terminals ll, and 12, asshown. The fittings 13 and Il are interconnected by an insulating sleeveIl of fiber or similar material, the

` the influence of the springs 42 until the stops M ends of the outersleeve 11 are provided to make a weathertight connection with thefittings 13 and Il Within the inner sleeve Il there is provided a bodyof solid arc extinguishing material in the form of rings l of magnesiumborate or boric acid. The rings 'il are stacked one above the other inalignment to provide a bore .Il through which a tubular terminal memberIl is arranged to be retracted for the purpose of extending andextinguishing an arc therein. 'I'he tubular terminal member Il isprovided with a centrally located passageway l! for the purpose ofconducting an arc extinguishing fluid into the arc space from a suitablereservoir for assisting in extinguishing the arc as will be describedmore in detail hereinafter. At the lower end of the tubular terminalmember Il the centrally located passageway l! branches off intoangularly directed nttings 'Il and 14 being threaded into the ends ofthe insulating sleeve Il as illustrated. Surrounding the sleeve 1I isanother sleeve ll of insulating material. The sleeve 1l may be formed ofa phenolic condensation product such as "Bakelite. A sleeve 11 ofsuitable insulating material such as glass or porcelain surrounds thesleeve ll and provides a weatherproof covering having high dielectriccharacteristics. Gaskets ll at the openings or apertures Il which, incombination with an opening Il in a terminal fitting B6, direct the arcextinguishing fluid both along the walls of the bore Il and over thefitting 8l and facilitate scavenging of the surfaces thereof.

The tubular terminal member Il is held in place by a strain element Ilone end of which is secured over a pin extending transversely throughthe lower end of the tubular terminal member Il. It will be noted thatthe transverse pin l5 is located at the top of the terminal fitting 88which ls threaded into the lower end of the tubular terminal member ll.The lower end of the strain element 8l is secured over a pin 8l whichextends transversely through a terminal fitting ll that is held by a nutIl in place on a metallic spider Il. The spider 90 is secured by meansof screws 0I to the fitting Il to which the lower terminal tube Il isconnected as previously described.

The terminal fittings 08 and 8l are interconnected by a plurality offusible elements 02. It will be observed that the fusible elements l2are bowed inwardly intermediate their ends in order to provide therequired length for the required timeA current characteristics withgiven spacing between the terminal fittings I6 and B8. The fusibleelements 82 are located symmetrically in the terminal fittings Il and I8about the centrally located strain element u.

Preferably the fusible elements 82 each comprise an outer sleeve of highmelting point metal such as 'silver and a core of low melting pointmetal such as tin. The details of construction of such a fusible elementare set forth in my Patent No. 2,243,135, and Patent No. 2,243,107, ofSigurd I. Lindell. The combination of a silver sheath and a tin coreprovides a high conductivity fusible element which operates at arelatively low temperature. Such a fusible element is particularlydesirable in fuses the normal current carrying capacity of which is ofthe order of 400 to 600 amperes.

It will be observed that the metallic spider Il is provided -withapertures 98 therein. These apertures are provided to permit the freeescape of the products of the arc formed between'the terminal fittings86 and It when the strain and fus'ble elements M and 92 have blown. The

products of the arc comprise incandescent gases and metallic particlesas well as 'arc extinguish- .ing fluid such as water vapor evolved fromthe a walls of the ,bore Il. It is desirable to cool and condense theseproducts cf the arc before they are permitted to escape to theatmosphere so as to' reduce the fire hazard to a minimum and preventarcing over to other energized conductors. For this purpose the productsof the src are caused to ow through a relatively narrow passageway 91between the inner surface of the terminal sleeve 12 and the outersurface of a body of solid arc` extinguishing material, such asmagnesium borate or boric acid, formed by a stack of rings 98 of thismaterial. These rings Il are centrally located on a suitable stud andare held in place by a nut |00 at the upper end as shown. The stud 09 isthreaded into a closure member |0| which in turn is threaded into thelower end of the terminal sleeve 12. Apertures |02 in the closure member|0| serve to vent the passageway 91 to the atmosphere. The use of solidarc extinguishing material such as boric acid or magnesium borate forcooling and condensing the products of the arc provides a beneficialeffect in that water vapor is evolved therefrom due to the heat of theproducts of the arc which tends to further cool and condense them and tosuppress ames which might otherwise escape to the atmosphere.

At its upper end thetubular terminal member Il is threaded into ametallic sleeve |00 which has an integrally formed radially extendingflange |01. A coil compression spring |00 is strained between theunderside of the iiange |01 and the upper surface of the ntting 12 andacts to bias the tubular terminal member 0| upwardly. It will berecalled that the strain element Il interconnects the terminal fittings00 and 00 and it will be understood that the upward movement of thetubular terminal member 0| is restrained as long as the strain element04 remains intact. The provision of the strain element Il relieves thefusible elements $2 of the application of any tension stress.

Since the circuit interrupter is intended for use in circuits in whichthe normal current carrying capacity is relatively high, such as 400 to600 amperes, it is desirable to provide a low resistance highconductivity path between the tubular terminal member Il and the sleeveterminal 1|. For this purpose the sleeve |06 is provided with anenlarged portion the outer surface I 09 of which forms a contact surfaceadapted to have contact engagement with flexible main contact fingers||0 that are carried by the fitting 13 and extend upwardly from itsupper surface as shown. The main contact fingers ||0 are curved adjacenttheir upper ends for receiving a garter spring which serves to bias thecontact fingers ||0 into intimate contact engagement with the contactsurface |00.

While it is desirable to have intimate contact engagement between themain contact fingers ||l and the contact surface |09 prior to circuitinterruption, it is also desirable to relieve the contact pressureincident to this contact engagement so that the tubular terminal member8| can move upwardly freely and quickly to extend and interrupt the arc.For this purpose the sleeve |06 is provided with a reduced section ||2so that after the rod-like terminal member 8| is moved upwardly a shortdistance the upper ends of the main contact fingers ||0 no longer engagethe sleeve |00.

Now it is desirable that there be provided a relatively low resistanceconducting path between the tubular terminal member 0| and the terminalsleeve 1i while the former is moving upwardly through the bore 80 toperform the circuit interrupting operation. In the past it has beencustomary to employ one or more flexible conductors to perform thisfunction. In

the circuit interrupter shown in Figures 8A and 8B of the drawings Ihave dispensed with the conventional form of flexible conductor and haveprovided auxiliary contact fingers III which extend downwardly from aring Ill' that has a'lpress fit with the fitting 10. 'Ihe lower ends ofthe auxiliary contact fingers III are curved for receiving a garterspring lil which acts to urge the contact fingers into good contactengagement with the outer surface of the tubular terminal member 0| asit moves upwardly through the bore Il. It will thus be seen that themain contact fingers |I0 provide the normal current carrying pathbetween the tubular terminal member 0| and the tube terminal 1|. At thesame time the auxiliary contact fingers H3 assist in this currentcarrying function. The auxiliary contact members III are not ofsufficient size and number to efficientlyperform this function alone.However. the auxiliary contact members ||l have sufficient currentcarrying capacity to carry the fault current during the relatively shortinterval such as a few cycles while the tubular terminal member 8| ismoving upwardly through the bore 0I and the arc incident to the circuitinterruption is being extinguished With a view to assisting inextinguishing low current arcs and to scavenging the walls of the bore00 after the arc has been extinguished a reservoir or capsule ||1 isprovided in the upper end of the sleeve |00 as shown. The reservoir orcapsule ||1 may be of the ISparklet type and is arranged to contain amaterial, such as carbon dioxide, which when released forms an arcextinguishing fluid and flows through the passageway 02 and apertures 00into the bore Il and arc space. The reservoir or capsule ||1 is providedwith a frangible diaphragm III which can be punctured for releasing thecontents. A coil compression spring Ill reacts between the lower 'end ofthe reservoir or capsule ||1 and the upper surface of a spider |20located between the tubular terminal member 0| and the sleeve |00 formaintaining the reservoir or capsule ||1 in spaced relation with respectto a pin or needle |2| carried by the spider |20. The reservoir orcapsule I |1 is hermetically sealed in place by a flexible bellows |22which, while permitting relative movement between the reservoir orcapsule ||1 and the tubular terminal member 0| prevents the escape ofarc extinguishing duid in any direction except through the ypassageway02.

When the strain and fusible elements Il and 02 are blown, the coilcompression spring Ill moves the tubular terminal member 0| upwardlythrough the bore 00 and an arc is drawn between the terminal fittings 0land l0. Because of the coil compression spring IIS, the reservoir orcapsule ||1 moves upwardly with the tubular terminal member 8| and inspaced relation thereto. Near the upper end of the stroke the uppersurface of the fiexible bellows |22 engages the under side 0f a disc |25threaded onto a stem |20 which projects through a closure member |21 atthe upper end of the tube terminal 1|. A coil compression spring |20,which normally biases the disc |25 downwardly, is compressed and a cap|29 at the upper end of the stem |26 is raised. The raising of the cap|20 indicates that the circuit interrupter 10 has operated and that itupward movement of the reservoir or capsule Ill permitted. However, thecoil compression spring III continues to move the sleeve III and tubularterminal member Ii upwardly through a limited extent because of theprovision of the coil compression spring ill and the ilexible bellows|22. 'Ihe pin or needle III then pierces the diaphragm III and rupturesthe same whereupon the contents of the reservoir or capsule III arereleased and the arc extinguishing fluid flows through the passageway l2into the -arc space where it performs thefunctions describedhereinbefore.

Referring now particularly to Figures 9A and B of the drawings, it willbe observed that the reference character Ill, generally, designates acircuit interrupter which comprises an insulatv ing housing I of glassorporcelain having a terminal I at its upperend and a terminal I at itslower end.

With a view to interconnecting the tubular terminal member III and thettlng I after the contact member Ill has moved out of engagement withthe contact lingers I, a flexible conductor I It is provided andconnected, as shown, to the iltting I at-the upper end and to the nttingIII at the lower end. The exible conductor I is coiled about the tubularterminal member IIJ so as to provide suiilcient length sion I'II.

Within the insulating -housing I thereis a replaceable cartridge,indicated generally at H1. The cartridge I" comprises a two layer sleeveIll of insulation having a terminal I at its upper end arranged to havecontact engagement with the terminal I at the upper end of the housingI". At its lower end the insulating sleeve I has a terminal I" in theform of a metallic sleeve which is arranged to be clamped to the lowerterminal I on the housing IM. Within the insulating sleeve I there arerings III of arc extinguishing material, such as magnesium borate orboric acid, which are stacked one above the other and provide a bore il!centrally thereof.

A tubular terminal member Ill' is arranged to be movably mounted withinthe bore Il! and it is held in place therein. as shown, by a strain wireIII which is supported by a cross-pin Ill carried by the terminal I". Afusible element I, preferably in the form of a silver wire,interconnects the terminal member I and the tubular terminal member I"and forms the principal current carrying element therebetween and isarranged to be fused under certain predetermined overload or shortcircuit conditions as is readily understood. The tubular terminal memberIll is provided with a centrally located longitudinally extendingaperture or passageway II'I through which an arc extinguishing medium isdischarged to assist in arc extinction as will be y presently described.

terminal member III is slidably mounted in a dtting III. The fitting IIIis arranged to be biased downwardly to carry with it the tubularterminal member I by a coil compression spring Il! which reacts betweenthe upper face of the tting III and the underside of a iltting IIIthreaded onto the lower end of the insulating sleeve III. It will beobserved that the sleevelike lower terminal member III of the cartridgeI" is threaded onto the fitting III so as to make good electricalcontact engagement therewith. Contact fingers I project downwardly fromthe fitting Ill and are arranged to have oontact engagement witha'cylindrical contact member Il! carried by and secured to .the tubularterminal member III. By means of the contact nngers i and contact memberIll the tubular terminal member Il) is directly connected through arelatively low resistance path to the lower terminal member Ill andthence tothe lower line terminal I".

' reservoir or capsule Threaded' into the lower end of the extension Illis a tubular connector i12 having a cap I'II threaded onto its lowerend. The connector Il! and cap Ill cooperate to hold a reservoir orcapaule |14 containing a material, such as carbon. dioxide, which whenreleased forms an arc extin guishing duid. The reservoir or capsule Illis closed or sealed bya diaphragm I'II which is arranged to be rupturedby a pin or needle III carried by a bridge member |11 at the lower endof the ltubular terminal member III. A coil compression spring I'Ilreacting between a nut I'Il threaded onto the lower end of the tubularterminal member IIS and the upper side of a dange Ill integrally formedwith the connector I'II,` serves to space the pin or needle IIl from thediaphragm Ill until certain predetermined conditions exist at which timethe diaphragm Ill is ruptured and the arc extinguishing medium isdischarged into the wsageway Ill. v

In operation, when the fusible element I and strain wire Ill are blown,the tubular terminal member ill is released to be moved downwardly underthe iniluence ofthe coil compression spring III. The cap Ill is moveddownwardly and passes through a frangible diaphragm III, such as micaortransparent plastic. and continues on outside of the tubular terminalmember ill to indicate that the device has operated. The iltting III andthe attached sleeve Ill continue to move downwardly until the undersideof the dtting III engages the upper edge of a stop ring Il! that issecured to the tubular terminal member Ill near its lower end. Whilefurther downward movement of the fitting iti is prevented, because ofthe kinetic energy in the tubular terminal member III, it continues tomove downwardly through the iltting IBI and extension Ill until the pinor needle Ill carried by the bridge I'II at its lower end punctures thediaphragm Ill. Further downward movement of the tubu-` lar terminalmember Ill is then arrested.

The arc extinguishing fluid released from the |14 is then dischargedthrough the passageway Ill and into the bore III in the solid arcextinguishing material III.

This arc extinguishing iluid assists in extinguishng the arc in the boreil! between the terminal members I and III by sweeping out the vaporsincident to the arc and deionizing the are space so as to lessen thelikelihood of the arc restriking on the next succeeding half cycle ofthe alternating current.

Since it is obvious that other embodiments of my invention can be madewithout departing from the spirit and scope thereof, it ls intendedAthat all matter shown in the accompanying drawings and describedhereinbefore shall be construed as illustrative and not in a limitingsense.

I claim as my invention:

1. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe fcrm of an arc extinguishing fluid, and means for releasing saidfluid when said tubular terminal member reaches a specified position toflow through said opening in said tubular terminal member and into thearc space for assisting in extinguishing an arc that may exist betweensaid terminal members and for scavenging the walls of said bore.

2. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an arc extinguishing iluid, said reservoir being mounted formovement with said tubular terminal member, and means for releasing saidfluid when said tubular terminal member reaches a specified position toflow through said opening in said tubular terminal member and into thearc space for assisting in extinguishing an arc that may exist betweensaid terminal members and ,for scavenging the walls of said bore.

3. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other `being tubular in character and movable through said bore,said tubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an arc extinguishing iluid, means mounting said reservoirfor movement with said tubular terminai member and permitting slightrelative movement therebetween, and means for releasing said fluid as aresult of said relative movement when said tubular terminal member ismoved to a predetermined position to ilow through said opening thereinand into the arc space for assisting in extinguishing an arc that mayexist between said terminal members and for scavenging the walls of saidbore.

4. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a, pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an src extinguishing fluid, means mounting said reservoirfor movement with said tubular terminal member and permitting slightrelative movenient therebetween, a normally extended ilexible bellowshermetically sealing said reservoir to said tubular terminal member, andmeans for collapsing said bellows and releasing said duid as a result ofsaid relative movement when said tubular terminal member is moved to apredetermined position to flow through said opening therein and into thearc space for assisting in extinguishing an arc that may exist betweensaid terminal members and for scavenging the walls of said bore.

5. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a .pair of relatively movableterminal members between which an src is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an arc extinguishing fluid, means mounting said reservoirendwise in alignment with said tubular terminal member for movementtherewith and permitting slight relative movement therebetween. springmeans biasing said reservoir away from said tubular terminal member, snormally extended flexible bellows hermetically sealing said reservoirto said tubular terminal member, and means for collapsing said bellowsand overcoming the biasing force of said spring means and releasing saidfluid as a result of said relative movement when said tubular terminalmember is moved to n predetermined position to now through said openingtherein and into the arc space for assisting in extinguishing an arcthat may exist between said terminal members and for scavenging thewalls of said bore.

6. In circuit interrupting apparatus, in combination a body or arcextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding msterial which when released is inthe form o! on arc extinguishing fluid, releasable means rethining saidmaterial in said reservoir, and means for releasing said releassbiemeans when said tubular terminal member is in a specified positionwhereby said src extinguishing iluid 1s released to flow through saidopening in said tubular terminal member and into the arc space forassisting in extinguishing an src that may exist between said terminalmembers and for scavenging the walls of said bore.

7. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a pair of relatively movabletermina] members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end o! said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form ot an src extinguishing uid, means mounting said reservoir formovement with said tubular terminal member, a rupturable diaphragmsealing said material in said reservoir, and means for rupturing saiddiaphragm when said tubular terminal member is moved to a predeterminedposition whereby said arc extinguishing iiuid is released to flowthrough said opening in said tubular terminal member and into the arcspace for assisting in extinguishing an arc that may exist between saidterminal members and for scavenging the walls oi said bore.

8. In circuit interrupting apparatus, in combination a body of areextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and mov- .able through said bore,said tubular terminal,

Vmovement therebetween, and means for rupturing said diaphragm as aresult of said relative movement when said tubular terminal member ismoved-to a predetermined position whereby said arc extinguishing fluidis released to ow through said opening in said tubular terminal membervand into the arc space for assisting in extingulshing an arc that mayexist between said terminal members and for scavenging the walls of saidbore.v

9. In circuit interrupting apparatus, in comblnation a body of arcextinguishing material having a bore, a pair ofrelatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an arc extinguishing fluid, means mounting said reservoirfor movement with said tubular terminal member and permitting slightrelative movement therebetween, a normally extended flexible bellowshermetically sealing said reservoir to said tubular terminal member, andmeans for collapsing said bellows and rupturing said diaphragm as aresult of said relative movement when said tubular terminal member ismoved to a predetermined position whereby said arc extinguishing fluidis released to flow through said opening in said tubular terminal memberand into the arc space for assisting in extinguishing an arc that mayexist between said terminal members and for scavenging the walls of saidbore.

10. In circuit interrupting apparatus, in combination a body of arcextinguishing material having a bore, a pair oi relatively movableterminal members between which an arc is adapted to be formed, one ofsaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable' through said bore,said tubular terminal member having an opening extending longitudinallytherethrough, a reservoir for holding material which when released is inthe form of an arc extinguishing fluid, means mounting said reservoirendwise in alignment with said tubular terminal member formovementrtherewith and permitting slight relative movement therebetween,a rupturable diaphragm sealing the end of said reservoir that isadjacent said tubular terminal member, spring means biasing saidreservoir away from said tubular terminal member,

a normally extended flexible bellows providingv a hermetically sealedconnection between said reservoir and said tubular terminal member,aneedle carried by and movable with said tubular terminal member anddirected toward said diaphragm, and stop means for arresting movementoi' said reservoir when said tubular terminal member is moved to apredetermined position whereupon said flexible bellows is collapsed, thebiasing force of said spring means is overcome and said needle rupturessaid diaphragm to release said arcextinguishing fluid to flow throughsaid opening in said tubular terminal member and into the arc space forassisting in extinguishing an arc that may exist between said terminalmembers and for scavenging the walls of said bore.

11. In circuit interrupting apparatus, in combination, a body of arcextinguishing material having a bore, a pair of terminals between whichan arc may be formed in said bore accompanied by the evolution of an arcextinguishing medium from the walls of said bore and discharge of flameand conducting particles, and means supplementary to said body of arcextinguishing material for cooling and condensing the products of thearc including means providing a restricted passageway at least one wallof which is provided by boric acid.

12. In circuit interrupting apparatus, in combination, a body oi arcextinguishing material having a bore, a pair of terminals between whichan arc may be formed in said bore accompanied by the evolution of an arcextinguishing medium from the walls of said bore and discharge of flameand conducting particles, and means supplementary to said body of arcextinguishing material for cooling and condensing the products of thearc including a body of boric acid over the outer surface of which saidproducts are caused tofiow, and an enclosure surrounding said body andproviding therewith a restricted passageway to cause said products tocome into rintimate contact with said body.

13. In circuit interrupting apparatus, in combination, a pair of lineterminal members disposed in insulated spaced relation, a pair ofarcingrterminal members between which an arc may be drawn, one arcingterminal member being stationarily mounted and connected to one of saidline terminal members and the other arcing terminal member beingmovable, and means for interconnecting said movable arcing terminalmember and the other line terminal member including-main contact fingermeans which carry,

the major portion of the current between said movable arcing terminalmember and said 'other line terminal member before movement of theformer is initiated, and auxiliary contact linger means arranged andadapted to carry the current between said movable arcing terminal memberand said other arcing terminal member after separation oi said maincontact means.

14. In clrcuitinterrupting apparatus, in combination, a pair of lineterminal members disposed in insulated spaced relation, a pair of arcingterminal members between which an arc may be drawn, one arcing terminalmember being stationarily mounted and connected to one o! said lineterminal members and the other arcing terminal member being movable andtubular in character, and means for interconnecting said tubular arclngterminal member and the other line terminal member including maincontact 5 means which carry the maior portion o! the current betweensaid tubular terminal member and said other terminal member beforemovement of the former is initiated, and auxiliary contact means carriedby said other terminal member and arranged and adapted to maintaincontact engagement with the outer surface of said tubular terminalmember as it moves away from said stationary arclng terminal member toextend the are therebetween.

l5. In circuit interrupting apparatus, in oombination, a pair of lineterminal members disposed in insulated spaced relation, a pair of arcingterminal members between which an are may be drawn, one arcing terminalmember being stationarily mounted and connected to one oi said lineterminal members and the other arcrnember being movable and tubular incharacter and having the end opposite the arcing end enlarged, aplurality of contact fin-- gers by the other line terminal member said.enlarged end portion o! said tubular terminal, and a plurality o!auxiliary. contact lingers carried by said other line terminal memberand adapted to engage the body of said tubular terminal member as itmoves sway from said stationary arclng terminal member to extend the arctherebetween.

l5. in circuit interrupting apparatus, in com blnation a body of arcextinguishing material having a bore, a pair of relatively movableterminal members between which an arc is adapted to be formed, one oisaid terminal members being located adjacent one end of said bore andthe other being tubular in character and movable through said bore, saidtubular terminal member having an opening extending longitudinellytherethrough, e. reservoir for holding material which when released isin the form of an are extinguishing fluid, said reservoir being movabletogether with tubular terminal member, ii oton connection between saidreservoir d tubular terminal member whereby relavo movement therebetweenis permitted, releasmeting in response to said relative movement betweeneoid reservoir and said tubular terminal rf robar whereby said aroextinguishing fluid la ed when tubular terminal reaches a li 'ing ebore, pair o relatively movable terminal members between which an arc isadapted to be formed, one of said terminal members being locatedadjacent one end of said bore and the other being tubular in characterand movable through bore, tubular terminal member opening extendinglongitudinally a reservoir for holding material released in the form ofan arc uid, said reservoir being movable -h said tubular terminalmember, a rineciion between said reservoir and ter member wherebyrelative 75 movement therebetween is permitted, said ren'b voir and saidtubular terminal member being biased apart, means for arresting movemento! said reservoir when it has been moved to a specined position whilesaid tubular terminal member continues to move, releasable meansretaining said material in said reservoir, and means for releasing saidreleasable means in response to said rela- Y tive movement between saidreservoir and said tubular terminal member whereby said arcextinguishing duid is released when said tubular terminal reaches aspecified position to ilow through said opening in said tubular terminaland into the arc space for assisting in extinguishing an arc that mayexist between said terminal members and scavenging the walls of saidbore.

18, In circuit interrupting apparatus, in combination1 a housing havinga bore, a pair of relatively movable terminal members between which anarc may be formed, one o! said terminal members being located at one endof said -bore and the other being tubular and movable through said bore.said tubular terminal member having an opening extending longitudinallytherethrough, operating means for moving said tubular terminal memberthrough said bore, a reservoir for holding material which when releasedis in the form of an arc extinguishing duid. rupturable means retainingsaid material 'in said reservoir, means mounting said reservoir formovement with said tubular terminal member and permitting slightrelative movement thenbetween, stop means for arresting movement o( saidreservoir when the same is moved with said tubular terminal member 'to apredetermined position while said tubular terminal member ycon-- tinuesto move, means carried by said tubular terminal member adapted to piercesaid rupturable means as a result oi said continued movement of saidtubular terminal member for releasing said are extinguishing fluid toflow through said open-y ing in said tubular terminal member and intothe arc space, said stop means being manually movable away from itsoperating position to per- ,r

mit removal of said tubular terminal member, and additional stop meansfor said operating' means for limiting movement thereof after the nrstmentioned stop means is moved away from its operating position tofacilitate removal o( said tubular terminal member.

i9. In circuit interrupting apparatus, a body having a bore, a pair ofrelatively movable terminal members between which an arc is adapted tobe formed, one of said terminal members being located adjacent one endoi' said bore and the other being tubular in character and movablethrough said bore. said tubular terminal member having an openingextending longitudinally therethrough, a reservoir for holding materialwhich when released is in the form of an arc extinguishing fluid, saidreservoir being mounted for movement with said tubular terminal member,and means for releasing said duid when said tubular terminal memberreaches a specied position to now through said opening in said tubularmember and into the arc space for assisting in extinguishing an arc thatmay exist between said terminal members and for scavenging the walls ofsaid bore.

20. In circuit interrupting apparatus, a body having a bore, a pair oi.'relatively movable tefminal members between which an arc is adapted tobe formed, one of said members being located adjacent one end of saidbore and the other being tubular in character and movable throughthrough, a reservoir mounted `'on said tubular ter- `minal memberadjacent one end thereof for said tubular terminal member beother endfor discharge thereli of said fluid, and means for releasing laid iluidasa result of relative movement betwedn said tubular terminal member andsaid reservoir. a

21. In circuit interruptingl apparatus, a body having a bore, a pair ofrelatively movable terminal members between which an are is adapted tobe formed, one of said members being located one end of said borfe andthe other becharacter and movable through tubular terminal member havingextending longitudinally there- -a reservoir mounted on said tubularterminal member at onelend thereof and yieldingly spaced therefrom withprovision for rela- Mve movement of said tubular terminal member towardsaid reservoir, the latter being disposed in discharge therethrough ofsaid iiuid, and means v'fil' rehasing said rduid as.a result of relativebetween said tubular terminal member and said reservoir, thelatter-being normalLv sealed and containing an arc extinguishing duidunder presmember. a reservoir mounted on said member at v one endthereof in substantial alignment therewith to discharge into said oneend of said tubular member and yieldingly held spaced therefrom forrelative movement of said tubular terminal member toward said reservoir,the latter being normally sealed and containing an arc extinguishingfluid under pressure, the other end of said tubular mem-ber being openfor discharge therethrough of said fluid, and means for releasing saidfluid as a result of relative movement of said tubular terminal membertoward said reservoir.

24. In circuit interrupting apparatus. in combination. a pair of lineterminal members disposed in insulated spaced relation, a pair of arcingterminal members between which an arc may be drawn. one arcing terminalmember being stationarily mounted and connected to one of said lineterminal members and the other arcing terminal member being movable, andmeans i'or interconnecting said movable arcing terminal member and theother line terminal member including main contact means which carry themajor portion of the current between said movable arcing terminal memberand said other line terminal member before movement of the former isinitiated and spring-biased g auxiliary contact means arranged andadapted to carry the current .between said movable arcing terminal mem-vber and said other arcins terminal member after separation of said maincontact means.

HUGH A. mmm.

